Boiler



T. c. ERVIN BOILER Filed Feb. 5, 1955 3 Sheets-Sheet 2 T. C. ERVIN May 12, 1936.

BOILER Filed Feb. 5, 1935 3 Sheets-Sheet 3 R Y NU R Er Ml w I A mv mB w T Patented May 12, 1936 UNITED "STATES PATENT OFFICE BOILER and the like, to accomplish these results and at the same time reinforce and strengthen the firebox, to simplify and improve-the mud ring,

to provide a more effective distribution of the water about the firebox sheet and to locate the manhole and steam dome inmore effective relation.

The foregoing and other desirable objects are attained in the present inventionby thenovel .features of construction, combinations, relations and arrangements of parts as hereinafter set forth, illustrated in the accompanying drawings and broadly covered in the claims annexed.

The attached drawings illustrate one practical commercial embodiment of the invention, but it will be appreciated that changes and modifications in structure may be made all within the true intent and broad scope of the invention.

Fig. 1 is a broken longitudinal sectional view .of an oil field boiler having features of the invention incorporated therein.

Fig. 2 is a broken part sectional andpart end elevation of the boiler.

Fig.3 is an enlarged broken sectional detail of the single thickness butt welded joint between the firebox sheet and the flange of the firebox door head showing the rows of supporting stay bolts at opposite sides of said weld, as on line 33 of Fig. 2.

Figs. 4, 5, 6 are broken sectional details illustrating successive stages inthe mud ring structure.

Figs. '7, 8, 9, are further broken part sectional details of the mud ring, Fig. 7 showing this structure as viewed from the rear, Fig. 8 as viewed from the side looking in the direction of arrow 8, Fig. '7 and Fig. 9 a horizontal section as on line 9-4] of Fig. '7.

As shown particularlyin Fig. 1, the firebox flue head It, and the firebox door head II, are made up with inwardly facing edge flanges I2, I3, opposed to and aligned with the opposite edges of the crown sheet or firebox sheet I4, and these parts are integrally united in such aligned relation by butt welds I5, I6.

At opposite sides of the welds I5, I6, and closely adjoining the same are the rows of stay bolts 55 [1, I8, extending between flanges I2, I3, and

Chattanooga, Tenn.

5, 1935, SeriallNo. 5,013

the surrounding wagon top-Wrapper sheet I 9, and 20,2 I, between the firebox sheet I4 and the wagon topwrapper sheet.

These rows of stay bolts at opposite sides of and close to the welds relieve the welds of stresses and amply carry the load.

In the illustration, the two welds are on :straight, parallel lines, extending up the sides and across the crown of the firebox. These welds .are therefore readily accomplished, but particular care is taken in making them. Thus .;for example,- as indicated in vFig. 3, the .edges ofthe head flanges and firebox sheet are chipped to remove any fractured or-burned metal and are lined up with an approximately 70angle to-be I filled in by the weld. Starting atthe fire-side, the weld is laid in bead-by-bead-and each layer is-thoroughly cleaned before :the next layer'is put on. After this, theopposite or=water-side isgouged and then welded up smoothlyin the same fashion as indicated at I6a.

This construction provides a firebox wall'of uniform thickness and free of any'uneventransmission otheat, such as necessarilypresent with lapped sheets and rivets extending therethrough as heretofore practiced. As a consequence, over-' heating of sheets and the burning of rivets and .leaks resulting therefrom :are entirely eliminated.

Also, as a result of the uniform'and moreefiicient heat transmissiomit is possible to develop a higher powenratingat-ausual or customary rate of firing.

With :this butt weld construction,'the head "flanges andfirebox sheet are of the same .diameter. regular and smooth. The diameter-"being the sameat both sides of the welds, the supporting and-reinforcing stay-bolts at opposite sides may be of the same length. r

This feature ofunitar-y, thoroughly reinforced structure is carried out in the mud ring as illustrated particularly in Figs. 4, 5 and. 6, by using a solid ring 22, drilled for staybolt openings 23, and having the inner and outer boiler sheets I4, I9, drilled with smaller registering openings 24, Fig. 4, which then while carefully held are reamed to the same diameter as in Fig. 5, after which both sheets and mud ring are tapped as at 25, Fig. 6, to take the screw-threaded staybolts 26, which latter are headed at 21.

Care is taken to remove burrs or anything that might prevent the boiler sheets from laying up closely against the sides of the mud ring and the sheets are bolted or clamped tightly in place against the mud ring when the three parts, that As a consequence, the flame flow is more is, the mud ring and the sheets at opposite sides are tapped, so that the staybolts will screw into edges of the sheets may be caulked and welded to the mud ring as indicated at 28.

The back sheet or head 29 is shown as flanged inside the wagon top wrapper at 30, Fig. 1, and Fig. 9 shows that where this flange meets the mud ring it seats within a recess or shouldered portion 3|, in the corner of the mud ring, with the wrapper sheet lapping it at this point. These outside corner portions asindicated in the latter view, may be held by shorter staybolts 32, screwthreaded in through the outer sheets and mud ring and headed over at the outside in the same manner as the through staybolts 26.

Thus the entire inside of the firebox presents a. relatively smooth surface, free of rivet heads.

Also, extra long rivets, such as heretofore used for securing mud rings are avoided. With such long rivets, it has not been possible heretofore to entirely plug the holes in the mud ring or boiler sheets, but with staybolts screw-threaded into both the sheets and the ring and headed at both ends, the holes inthe joined parts are com pletely' closed and the sheets drawn together 1 against the ring.

In'Fig. 2, the sides of the firebox sheet are shown at 33, inclined inwardly toward the top,

so as, with thesubstantially parallel sides 34 of the wagon top wrapper sheet, to provide water spaces 35, at the sides of the firebox, gradually widening toward the top. This accelerates water circulation at the sides and over the top of the firebox and the inward slopes of the firebox sheet present more effective heat absorption surfaces to the fire.

' The dome 36 is indicated in Fig. 1, as located on the middle course 31, of the boiler, as far forward from the firebox as practicable. This ivesthe wet steam coming over from the firebox the more opportunity to dry out or lose moisture before entering the dome.

fA manhole-is indicated at 38, Fig. 1, in the top of the boiler shell back of the dome, that is, be-

tween the latter and the back head and as close as possible over the firebox tube head, where "washing and removing of scale is most difficult. With the solid unitary construction disclosed,

the firebox may be built to greater length with safety, to provide a better ratio of furnace volume to heating surface. Improved generation of steam is thus made possible as will be realized when it is considered that approximately 60% of the Water is evaporated over and around the firebox. The entire surface exposed to the fire is of uniform thickness. There is thus no uneven transmission of heat, such as occasioned by lapped sheets and rivet heads. Overheating, leaking and burned rivets are thus eliminated and with the same firing a much greater power output is attained.

What is claimed is:

i '1. A mud ring structure, comprising outer and inner boiler sheets, a mud ring between said sheets, said sheets and intermediate mud ring having aligned tapped openings therethrough, staybolts screwed in said tapped openings through said outer and inner boiler sheets and mudring, the ends of said staybolts being upset and expandedinto the screw threads in said boiler sheets andmud ring, thereby entirely plugging the same and being compressed longitudinally to bind the boiler sheets against the sides of the mud ring. I

2. The herein disclosed method of boiler manufacture, which comprises drilling a mud ring with staybolt openings, drilling outer and inner boiler sheets with smaller registering openings and while holding said sheets closely against opposite faces of the mud ring, reaming said registered sheet and mud ring openings to the same diameter and screw-threading through all three held parts, screwing staybolts through said threaded openings in the outer and inner boiler sheets and intermediate mud ring while the parts are so held and then upsetting the ends of said staybolts to thereby completely plug the screwthreaded openings in mud ring and boiler sheets and bind the boiler sheets against the opposite faces of the mud ring.

3. The herein disclosed method of boiler manufacture, which comprises drilling a mud ring with staybolt openings, drilling outer and inner boiler sheets with smaller registering openings and While holding said sheets closely against opposite facesof the mud ring, reaming said registered sheet and mud ring openings to the same diameter and screw-threading through all three held parts, screwing staybolts through said threaded openings in the outer and inner boiler sheets and intermediate mud ring while the parts are so held and then upsetting the ends of said staybolts to thereby completely plug the screwthreaded openings in mud ring and boiler sheets and bind the boiler sheets against the opposite faces of the mud ring and caulking and welding the edges of the boiler sheetsto the opposite 'faces of the mud ring below the headed staybolts as a precaution against expansion leaks.

THOMAS C. ERV'IN. 

